My guess is that they're probably going to spend some time building their own CDN / image storage. I think they used some combination of dedicated servers, RDBM

My guess is that they're probably going to spend some time building their own CDN / image storage. I think they used some combination of dedicated servers, RDBMS, CloudFlare, and AWS. They could save some significant operating costs, without sacrificing a lot of of customer happiness by putting together their own datacenter, and hosting a handful of edge sites (a rack or two, and then fast failover out of the rack). I imagine that the traffic curve on images drops off pretty quickly after a point, and stays down.